01 - Lightly grease the inside of the slow cooker with olive oil or nonstick cooking spray to prevent sticking.
02 - In a small bowl, whisk together the minced garlic, grated Parmesan, chicken broth, heavy cream, olive oil, Italian herbs, paprika, salt, and black pepper until well combined.
03 - Arrange the halved baby potatoes and diced onion in an even layer at the bottom of the slow cooker.
04 - Place the chicken breasts on top of the vegetable layer, ensuring they are not overcrowded.
05 - Evenly pour the garlic Parmesan sauce over the chicken and vegetables, coating as much surface area as possible.
06 - Cover and cook on high heat for 4 hours or on low heat for 7 hours, until the chicken reaches an internal temperature of 165°F and the potatoes are fork-tender.
07 - If using, stir in the baby spinach during the last 30 minutes of cooking and allow it to wilt.
08 - Remove the lid, sprinkle with chopped fresh parsley and additional grated Parmesan cheese before serving.